Abstract PD1-03: A multicenter phase II study evaluating the efficacy of nivolumab plus paclitaxel plus bevacizumab triple-combination therapy as a first-line treatment in patients with HER2-negative metastatic breast cancer: WJOG9917B NEWBEAT trial

Abstract

Abstract Background: PD-1 inhibitors have been developed for various cancer types, including breast cancer. Potential synergistic effects of nivolumab, paclitaxel and bevacizumab in combination was reported in preclinical models. Therefore, we initiated this investigator-initiated trial to evaluate the efficacy and safety of nivolumab + paclitaxel + bevacizumab therapy for metastatic breast cancer (MBC) patients (pts).Methods: This is a Phase II, multi-center, single-arm study to evaluate the efficacy and safety of nivolumab + paclitaxel + bevacizumab combination therapy as a first-line treatment for pts with HER2— MBC. Patients received nivolumab 240 mg/body on day 1, 15, paclitaxel 90 mg/m2 on day1, 8, 15, and bevacizumab 10 mg/kg on day1, 15 every 4 weeks until disease progression or intolerable toxicity experienced. The primary endpoint is the objective response rate (ORR) by independent central assessment. Key secondary endpoints include disease control rate (DCR: CR+PR+SD), progression free survival (PFS), overall survival, and the toxicity. The threshold and expected ORR are 55% and 70%, respectively, and 47 patients are needed to ensure a statistical power of 80% (α=0.10). Results: From February 2018 to October 2018, 57 female HER2— MBC pts were enrolled. Thirty-nine pts (68%) were with hormone receptor-positive (HR+), and 18 pts (32%) were with triple negative breast cancer (TNBC). ORR based on investigator assessment was 75.4%, and DCR was 96.4%. ORR was 71.7% (28/39) in pts with HR+ breast cancer and 83.3% (15/18) in pts with TNBC. Median PFS was not reached with median follow-up time of 10.7 months, and PFS rate at 12 months was 75.8% (95%CI: 60.9-86.2). Median OS was not reached and OS rate at 12 months was 87.1% (95%CI: 70.7-94.9). Thirty-five pts (59%) were still under treatment at the data cut-off date (1st June 2019). All pts had ≥1 AE; 58% of pts had Grade 3 or 4 AEs and 17% of pts had Grade 3 or 4 immune related-AEs. Twenty two percent of pts had serious AEs (SAE), and 12% of pts had nivolumab-related SAEs. Among the pts with nivolumab-related SAEs, 71% of them had recovered from SAEs. No treatment-related death was observed. Primary endpoint of ORR by independent central assessment and subset analysis with PD-L1 expression on tumor tissue (CPS, TPS by 28-8 antibody and IC, TC by SP142 antibody) will be presented at the symposium. Conclusions: This is the first study showing the promising efficacy of Nivolumab in combination with paclitaxel plus bevacizumab as a first line treatment for HER2— MBC. This triple-combination strategy for breast cancer warrants further study. Clinical trial information: UMIN000030242.Funding: This trial is sponsored by Ono pharmaceutical company. ResponseTotal100% (N = 57)Partial response (PR)75.4% (N = 43)Stable disease (SD)21.1% (N = 12)Progressive disease (PD)1.7% (N = 1)Objective response rate (ORR)75.4% (N = 43)Disease control rate (DCR) :CR+PR+SD96.4% (N = 55) Citation Format: Yukinori Ozaki, Toru Mukohara, Junji Tsurutani, Masato Takahashi, Koji Matsumoto, Manabu Futamura, Norikazu Masuda, Shigehisa Kitano, Kenichi Yoshimura, Hironobu Minami, Toshimi Takano. A multicenter phase II study evaluating the efficacy of nivolumab plus paclitaxel plus bevacizumab triple-combination therapy as a first-line treatment in patients with HER2-negative metastatic breast cancer: WJOG9917B NEWBEAT trial [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr PD1-03.